In current lumber processing systems, pieces of lumber are typically fed into a processing machine (e.g. a planer) in three stages. In the first stage, the pieces are conveyed on smooth chains along a conveyor toward a transfer. The pieces are crowded together to form a continuous edge to edge mat of lumber on the conveyor, with each piece oriented perpendicular to the direction of travel.
In the second stage, the transfer accepts the pieces from the conveyor. The transfer may include a plurality of rollers (e.g. pineapple rollers) rotating around an axis parallel to the first stage conveyor. As the leading piece of lumber in the mat reaches the transfer, the rollers contact the piece of lumber, abruptly changing the direction of travel by ninety degrees and accelerating the piece lineally along the transfer at a high rate of speed toward a downstream processing machine. The directional change and sudden acceleration produces large gaps between the pieces.
In the third stage, the lumber pieces are fed individually into a processing machine, such as an edger. The large gaps between successive lumber pieces reduce efficiency at the processing machine. Further, deceleration of the lead piece over a short distance can cause the following piece to collide with the lead piece. Because the following piece is traveling at a high rate of speed, such collisions can damage the pieces, cause work flow stoppages, and necessitate costly clean-ups and repairs.
For this reason, current systems require a relatively long (e.g. 40 ft.) intermediate conveyor, or “bridge,” between the transfer and the processing machine. This allows sufficient distances for deceleration of the lead piece relative to the following piece, providing minimization of both gaps and collisions.